"... The creation of believable and endearing characters in computer graphics presents a number of technical challenges, including the modeling, animation and rendering of complex shapes such as heads, hands, and clothing. Traditionally, these shapes have been modeled with NURBS surfaces despite the seve ..."

The creation of believable and endearing characters in computer graphics presents a number of technical challenges, including the modeling, animation and rendering of complex shapes such as heads, hands, and clothing. Traditionally, these shapes have been modeled with NURBS surfaces despite the severe topological re-strictions that NURBS impose. In order to move beyond these re-strictions, we have recently introduced subdivision surfaces into our production environment. Subdivision surfaces are not new, but their use in high-end CG production has been limited. Here we describe a series of developments that were required in order for subdivision surfaces to meet the demands of high-end production. First, we devised a practical technique for construct-ing provably smooth variable-radius fillets and blends. Second, we developed methods for using subdivision surfaces in clothing sim-ulation including a new algorithm for efficient collision detection. Third, we developed a method for constructing smooth scalar fields on subdivision surfaces, thereby enabling the use of a wider class of programmable shaders. These developments, which were used extensively in our recently completed short film Geri’s game, have become a highly valued feature of our production environment.

...s rise to a collection of special cases around extraordinary points. We chose to avoid these special cases by adopting a finitedifference approach, approximating the clothing with a mass-spring model =-=[18]-=- in which all the mass is concentrated at the control points. Away from extraordinary points, Catmull-Clark meshes under subdivision become regular quadrilateral grids. This makes them ideally suited ...

"... We describe work on the visualization of bibliographic data and, to aid in this task, the application of numerical techniques for multidimensional scaling. Many areas of scientific research involve complex multivariate data. One example of this is Information Retrieval. Document comparisons may be d ..."

We describe work on the visualization of bibliographic data and, to aid in this task, the application of numerical techniques for multidimensional scaling. Many areas of scientific research involve complex multivariate data. One example of this is Information Retrieval. Document comparisons may be done using a large number of variables. Such conditions do not favour the more wellknown methods of visualization and graphical analysis, as it is rarely feasible to map each variable onto one aspect of even a three-dimensional, coloured and textured space. Bead is a prototype system for the graphically-based exploration of information. In this system, articles in a bibliography are represented by particles in 3-space. By using physically-based modelling techniques to take advantage of fast methods for the approximation of potential fields, we represent the relationships between articles by their relative spatial positions. Inter-particle forces tend to make similar articles move closer to on...

"... Figure 1: Multiple deformable models simulation: This sequence shows the positions of the objects at three time instances in a simulation. The environment initially consists of 10 deforming objects represented using 5.5K triangles. As the simulation proceeds, the objects break into 25 sub-objects. O ..."

Figure 1: Multiple deformable models simulation: This sequence shows the positions of the objects at three time instances in a simulation. The environment initially consists of 10 deforming objects represented using 5.5K triangles. As the simulation proceeds, the objects break into 25 sub-objects. Our algorithm is able to perform collision and separation distance computations, including self-collisions, among dynamically generated objects within 120 ms on a high-end PC. We present novel algorithms to perform collision and distance queries among multiple deformable models in dynamic environments. These include inter-object queries between different objects as well as intra-object queries. We describe a unified approach to compute these queries based on N-body distance computation and use properties of the 2 nd order discrete Voronoi diagram to perform N-body culling. Our algorithms involve no preprocessing and also work well on models with changing topologies. We can perform all proximity queries among complex deformable models consisting of thousands of triangles in a fraction of a second on a high-end PC. Moreover, our Voronoi-based culling algorithm can improve the performance of separation distance and penetration queries by an order of magnitude.

"... Real-time simulation and animation of global deformation of 3D objects, using finite element method (FEM), is difficult due to the following 3 fundamental problems: (1) The linear elastic model is inappropriate for simulating large motion and large deformations (unacceptable distortion will occur); ..."

Real-time simulation and animation of global deformation of 3D objects, using finite element method (FEM), is difficult due to the following 3 fundamental problems: (1) The linear elastic model is inappropriate for simulating large motion and large deformations (unacceptable distortion will occur); (2) The time step for dynamic integration has to be drastically reduced to simulate collisions; (3) The size of the problem (the number of elements in the FEM mesh) is one order of magnitude larger than a 2D problem.

"... Force feedback coupled with a real-time physically realistic graphic display provides a human operator with an artificial sense of presence in a virtual environment. Furthermore, it allows a human operator to interact with the virtual environment through "touch". In this paper, we describe ..."

Force feedback coupled with a real-time physically realistic graphic display provides a human operator with an artificial sense of presence in a virtual environment. Furthermore, it allows a human operator to interact with the virtual environment through &quot;touch&quot;. In this paper, we describe a haptic simulation system that allows a human operator to perform real-time interaction with soft 3D objects that go through large global deformations. We model and simulate such a global deformation using geometrically nonlinear finite element methods (FEM). We also introduce an efficient method that computes the force feedback, in real-time, by simulating the collision between the virtual &quot;proxy&quot;andthedeformable object. To perceptually satisfy a human operator, haptics requires a much higher update frequency (at least 1000Hz) than graphics. We update the graphics using full simulation and interpolate the fully simulated states at a higher frequency to render haptics. The interpolation is made possible by intentionally delaying the display (both graphics and haptics) by one full simulation cycle.

"... We present a realistic skeletal musculo-tendon model of the human hand and forearm. The model permits direct forward dynamics simulation, which accurately predicts hand and finger position given a set of muscle activations. We also present a solution to the inverse problem of determining an optimal ..."

We present a realistic skeletal musculo-tendon model of the human hand and forearm. The model permits direct forward dynamics simulation, which accurately predicts hand and finger position given a set of muscle activations. We also present a solution to the inverse problem of determining an optimal set of muscle activations to achieve a given pose or motion; muscle fatigue, injury or atrophy can also be specified, yielding different control solutions that favour healthy muscle. As there can be many (or no) solutions to this inverse problem, we demonstrate how the space of possible solutions can be filtered to an optimal representative. Of particular note is the ability of our model to take a wide array of joint interdependence into account for both forward and inverse problems. Given kinematic postures, the model can be used to validate, predict or fill in missing motion and improve coarsely specified motion with anatomic fidelity. Lastly, we address the visualization and understanding of the dynamically changing and spatially compact musculature using various interaction techniques. 1.

"... In this paper we address the problem of collision detection and response in real-time animation systems. We describe an approach, which approximates objects using sphere-trees, and uses an interruptible detection algorithm to approximately test for collisions between them, trading accuracy for speed ..."

In this paper we address the problem of collision detection and response in real-time animation systems. We describe an approach, which approximates objects using sphere-trees, and uses an interruptible detection algorithm to approximately test for collisions between them, trading accuracy for speed. A model of human visual perception of collisions is used to decide which collisions deserve more processing time. Collision processing is then scheduled to minimise the perceived inaccuracy within the time available. In response to such approximate collisions, a new adaptive collision response algorithm is presented, which also uses sphere-trees to approximate the appropriate response for colliding objects. 1 INTRODUCTION Many interactive animation systems, such as games or simulations, require large numbers of virtual entities which are moving and interacting with each other, and/or with one or more users. In these applications, we cannot predict in advance how the user or the entities ...

"... Figure 1: Top: Pinhole camera image from an upcoming feature film. Bottom: Sample results of our depth-of-field algorithm based on simulated diffusion. We generate these results from a single color and depth value per pixel, and the above images render at 23–25 frames per second. The method is desig ..."

Figure 1: Top: Pinhole camera image from an upcoming feature film. Bottom: Sample results of our depth-of-field algorithm based on simulated diffusion. We generate these results from a single color and depth value per pixel, and the above images render at 23–25 frames per second. The method is designed to produce film-preview quality at interactive rates on a GPU. Fast preview should allow greater artistic control of depth-of-field effects. Accurate computation of depth-of-field effects in computer graphics rendering is generally very time consuming, creating a problematic workflow for film authoring. The computation is particularly challenging because it depends on large-scale spatially-varying filtering that must accurately respect complex boundaries. A variety of real-time algorithms have been proposed for games, but the compromises required to achieve the necessary frame rates have made them them unsuitable for film. Here we introduce an approximate depth-of-field computation that is good enough for film preview, yet can be computed interactively on a GPU. The computation creates depth-of-field blurs by simulating the heat equation for a nonuniform medium. Our alternating direction implicit solution gives rise to separable spatially varying recursive filters that can compute large-kernel convolutions in constant time per pixel while respecting the boundaries between in-focus and out-of-focus objects. Recursive filters have traditionally been viewed as problematic for GPUs, but using the well-established method of cyclic reduction of tridiagonal systems, we are able to vectorize the computation and achieve interactive frame rates. Direction Implicit Methods, GPU, Tridiagonal Matrices, Cyclic Reduction. 1

"... Future interactive entertainment applications will feature the physical simulation of thousands of interacting objects using explosions, breakable objects, and cloth effects. While these applications require a tremendous amount of performance to satisfy the minimum frame rate of 30 FPS, there is a d ..."

Future interactive entertainment applications will feature the physical simulation of thousands of interacting objects using explosions, breakable objects, and cloth effects. While these applications require a tremendous amount of performance to satisfy the minimum frame rate of 30 FPS, there is a dramatic amount of parallelism in future physics workloads. How will future physics architectures leverage parallelism to achieve the real-time constraint? We propose and characterize a set of forward-looking benchmarks to represent future physics load and explore the design space of future physics processors. In response to the demand of this workload, we demonstrate an architecture with a set of powerful cores and caches to provide performance for the serial and coarse-grain parallel components of physics simulation, along with a flexible set of simple cores to exploit fine-grain parallelism. Our architecture combines intelligent, application-aware L2 management with dynamic coupling/allocation of simple cores to complex cores. Furthermore, we perform sensitivity analysis on interconnect alternatives to determine how tightly to couple these cores. Categories and Subject Descriptors:

... engine is a heavily modified implementation of the publicly available Open Dynamics Engine (ODE) version 0.7 [7]. ODE follows a constraint-based approach for modeling articulated figures, similar to =-=[5, 18]-=-, and it is designed for efficiency rather than accuracy. Our implementation supports more complex physical functions, including cloth simulation, pre-fractured objects, and explosions. We have parall...

"... The ability to detect failures and to analyze their causes is one of the preconditions of truly autonomous mobile robots. Especially online failure detection is a complex task, since the effects of failures are typically difficult to model and often resemble the noisy system behavior in a fault-free ..."

The ability to detect failures and to analyze their causes is one of the preconditions of truly autonomous mobile robots. Especially online failure detection is a complex task, since the effects of failures are typically difficult to model and often resemble the noisy system behavior in a fault-free operational mode. The extremely low a priori likelihood of failures poses additional challenges for detection algorithms. In this paper, we present an approach that applies Gaussian process classification and regression techniques for learning highly effective proposal distributions of a particle filter that is applied to track the state of the system. As a result, the efficiency and robustness of the state estimation process is substantially improved. In practical experiments carried out with a real robot we demonstrate that our system is capable of detecting collisions with unseen obstacles while at the same time estimating the changing point of contact with the obstacle. 1